Sophisticated representations of objects provide the foundation for conceptual knowledge of the world, for language, for quantitative reasoning, and for social interactions. The ability to form such representations is therefore critically important for infants'developing comprehension of the world. Understanding how infants'representations of objects develop is central to our knowledge of infant cognition, and provides insight into both typical and atypical patterns of development. For example, children with Williams Syndrome and Autism Spectrum Disorder have known deficits in their visual processing. Identifying typical patterns of development provides a key starting point for understanding such deficits. The broad goal of this project is to deepen our understanding of how infants become able to form increasingly sophisticated object representations across the first year of life. Specifically, we will study the abilities that make it possible for infants to represent new kinds of object features. In particular, using measures of infant looking at computer generated images and object manipulation, we will (a) examine the role of motor development in infants'representation of the surface properties of objects (Experiments 1-4), and (b) investigate the role of developing memory and attention skills on the features infants represent (Experiments 5-7). These two aims are well supported by the literature. It has long been held that infants learn about objects in their environment through action. The proposed work builds on this tradition. In addition, researchers have come to believe that objects and events are represented in the moment, during the acts of perceiving, attending, comparing, and so on. The present work extends this approach to understanding how infants create representations of the objects and events they encounter. The findings from this project will contribute to our understanding of atypical patterns of development, such as those characterizing Williams Syndrome and Autism Spectrum Disorder. Autistic children have deficits in representing actions;Williams syndrome individuals have deficits in ventral stream processing. This project, will provide insight into typical development of infants'representation or action and of features likely processed by the ventral and dorsal pathways. Thus, the typical development outlined here will provide an important point of reference for understanding the atypical development in such disorders. PUBLIC HEALTH RELEVANCE Children with Williams Syndrome and Autism Spectrum Disorder have known deficits in their visual processing. Identifying typical patterns of development provides a key starting point for understanding such deficits. The broad goal of this project is to deepen our understanding of how infants become able to form increasingly sophisticated object representations across the first year of life, and therefore providing a foundation for our understanding of atypical patterns of development.